1. Field of the Invention
This invention relates to a method for reducing the microbial content of surfaces, and more particularly, to compositions containing a stable, high purity, free-flowing, substantially anhydrous complex of PVP-H.sub.2 O.sub.2 for treating acne vulgaris.
2. Description of the Prior Art
Stabilized H.sub.2 O.sub.2 compositions have found wide utility in commercial and industrial applications, e.g. as antiseptics, disinfectants, sterilization agents, bleaching materials, washing concentrates, etchants, in cosmetic preparations, and as a catalyst in polymerizations requiring a free radical source. In biological applications which require an antiseptic, disinfectant or sterilization agent, such H.sub.2 O.sub.2 compositions require release of an effective amount of oxygen at a desired rate.
Shiraeff, in U.S. Pat. Nos. 3,376,110 and 3,480,557, reacted hydrogen peroxide and PVP in an aqueous solution of the components. The process involved mixing predetermined amounts of PVP and a large excess of aqueous H.sub.2 O.sub.2, e.g. 50% aqueous solutions, and evaporating the solution to dryness. The Shiraeff composition was described as not necessarily anhydrous due to the hydrophilic nature of the PVP and the water present in the reaction solution. Shiraeff stated that water could be tolerated, however, if it did not affect the solid dry characteristics of the complexes. The H.sub.2 O.sub.2 content of the composition was given as being at least 2%, and preferably 4.5 to 70% by weight. Prolonged drying of the composition in an attempt to reduce the water content, however, resulted in loss of H.sub.2 O.sub.2 from the complex, forming a brittle, transparent, gummy, amorphous product of non-reproducible consistency. The resultant hard, brittle chips had a variable H.sub.2 O.sub.2 content ranging from about 3.20 to 18.07% by weight, depending upon the drying times, and a considerable amount of water.
The Shiraeff PVP-H.sub.2 O.sub.2 material did not attain commercial success because the product (1) was not a free-flowing powder; (2) its water and peroxide content varied widely; (3) it had consistency and reproducibility problems; and (4) the aqueous laboratory process could not be scaled up due to great loss of H.sub.2 O.sub.2 during drying.
Acne vulgaris is an inflammatory disease of the pilosebaceous glands characterized by an eruption of the skin, often pustular in nature but not suppurative. Acne is a common affliction of the adolescent and affects a small but significant percentage of the adult population. Acne lesions are of four basic types: comedones (blackheads or whiteheads), papules, pustules, and cysts (or nodules). Various topical agents are utilized in the treatment of acne and these include sulfur, resorcinol, salicylic acid, benzoyl peroxide, vitamin A acid and topical antibiotics. Acne involvement results in unslightly lesions, particularly on the face, and in some cases results in severe scarring.
Accordingly, an object of the invention is to provide a method for treating acne vulgaris with a composition containing a stable, high purity, substantially anhydrous complex of PVP-H.sub.2 O.sub.2 in a defined molar ratio of 1:1 of constituents and which is a free-flowing, fine white powder.
Another object of the invention is to provide a stick formulation of such composition for treating acne vulgaris in a commercial and consumer-acceptable manner.
Still another object of the invention is to provide a method for reducing the microbial content of skin surfaces afflicted with acne vulgaris with a microbial amount of a 1:1 complex of PVP-H.sub.2 O.sub.2 having an H.sub.2 O.sub.2 activity of at least 3%.